Vehicular latch with direct locking of pawl

ABSTRACT

A vehicle latch is provided having a ratchet, a primary pawl, an auxiliary ratchet and a secondary pawl, and further including a gear that is movable to a secondary pawl locking position wherein the gear directly blocks movement of the secondary pawl and locks the secondary pawl in an auxiliary ratchet holding position to prevent premature or unintended opening of the latch.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/410,634 filed Dec. 23, 2014, which is a National Stage ofInternational Application No. PCT/CA2013/000577 filed Jun. 17, 2013,which claims the benefit of U.S. Provisional Patent Application No.61/663,881 filed Jun. 25, 2012. The entire content of each of the aboveapplications is incorporated herein by reference.

FIELD

The disclosure generally relates to the art of vehicle latches and morespecifically vehicle latches that utilize double pawl arrangements.

BACKGROUND

Double pawl arrangements are known in the latching art. The double pawlarrangement may utilize a primary pawl and ratchet connected to asecondary pawl and ratchet. The connection may be configured such thatonly a portion of the forces experienced by the primary pawl and ratchetare applied to the secondary pawl and ratchet, thus requiring arelatively low effort to release the latch. While a low effort torelease the latch is desirable, a problem can occur that an unbalancedforce may release the latch in unintended circumstances such as during acrash event. It would be desirable to prevent such events.

In addition, in double pawl arrangements both pawls must be reset totheir locked positions. Biasing means such as springs are conventionallyemployed for such purpose. But over time, these biasing forces maydegrade, or may be insufficient occasionally to cope with otherimpediments to returning the pawls to their respective locked positions.An at least partial solution is sought to such problems.

SUMMARY

In one aspect a vehicle latch is provided having a ratchet, a primarypawl, an auxiliary ratchet and a secondary pawl, and further including agear that is movable to a secondary pawl locking position wherein thegear directly blocks movement of the secondary pawl and locks thesecondary pawl in an auxiliary ratchet holding position to preventpremature or unintended opening of the latch.

In an embodiment of the above noted aspect, the ratchet is movablebetween a striker capture position wherein the ratchet is positioned toretain a striker and a striker release position wherein the ratchet ispositioned to release the striker. The ratchet may be biased towards thestriker release position. The primary pawl is movable between a ratchetholding position wherein the primary pawl is positioned to hold theratchet in the striker capture position and a ratchet release positionwherein the primary pawl permits the movement of the ratchet out of thestriker capture position. The primary pawl may be biased towards theratchet holding position. The auxiliary ratchet is operatively connectedto the primary pawl and is movable between a primary pawl enablingposition in which the auxiliary ratchet permits the primary pawl to moveto the ratchet holding position and a primary pawl disabling position inwhich the auxiliary ratchet positions the primary pawl in the ratchetrelease position. The secondary pawl is movable between an auxiliaryratchet holding position in which the secondary pawl is positioned tohold the auxiliary ratchet in the primary pawl enabling position, and anauxiliary ratchet release position in which the secondary pawl ispositioned to permit movement of the auxiliary ratchet to the disablingposition. The secondary pawl may be biased towards the auxiliary ratchetholding position.

In another aspect, a vehicle latch is provided that includes a ratchet,a primary pawl, an auxiliary ratchet and a secondary pawl, and furtherincluding a gear that is operatively connected to the secondary pawl.The gear is rotatable to cause movement of the secondary pawl towards anauxiliary ratchet holding position and is rotatable to cause movement ofthe secondary pawl towards the auxiliary ratchet release position. Thegear is rotatable to a secondary pawl locking position to lock thesecondary pawl in the auxiliary ratchet holding position. The gear isrotatable to a reset position during which the gear causes movement ofthe secondary pawl to the auxiliary ratchet holding position after theauxiliary ratchet has moved to the primary pawl enabling position. Insome embodiments the gear causes movement of the auxiliary ratchet tothe primary pawl enabling position. A reset position sensor is providedand is positioned to detect the presence of the gear in the resetposition.

In yet another aspect, a vehicle latch is provided, comprising aratchet, a pawl and a gear. The ratchet is movable between a strikercapture position wherein the ratchet is positioned to retain a strikerand a striker release position wherein the ratchet is positioned torelease the striker. The ratchet is biased towards the striker releaseposition. The pawl is movable between a first position and a secondposition. When the ratchet is in the closed position and the pawl is inthe first position, the pawl at least indirectly holds the ratchet inthe closed position. When the pawl is in the second position, the pawlpermits movement of the ratchet to the open position. The gear ismovable to a pawl locking position wherein a gear locking surface on thegear directly blocks movement of a pawl locking surface on the pawl sothat the gear directly locks the pawl in the second position.Optionally, the pawl is a secondary pawl and there is a primary pawl andan auxiliary ratchet provided.

In yet another aspect, a vehicle latch is provided and includes a motor,a worm, a gear, a primary ratchet, a primary pawl, an auxiliary ratchetand a secondary pawl all extend in planes that are parallel to eachother.

In another embodiment of the above noted aspect, the ratchet ispivotally mounted to the housing via a primary ratchet pin joint and ismovable between a striker capture position wherein the ratchet ispositioned to retain a striker and a striker release position whereinthe ratchet is positioned to release the striker. The ratchet may bebiased towards the striker release position. The primary pawl ispivotally mounted to the auxiliary ratchet via a primary pawl pin jointand is movable between a ratchet holding position wherein the primarypawl is positioned to hold the ratchet in the striker capture positionand a ratchet release position wherein the primary pawl permits themovement of the ratchet out of the striker capture position. The primarypawl may be biased towards the ratchet holding position. The auxiliaryratchet is pivotally mounted to the housing via an auxiliary ratchet pinjoint and is operatively connected to the primary pawl and is movablebetween a primary pawl enabling position in which the auxiliary ratchetpermits the primary pawl to move to the ratchet holding position and aprimary pawl disabling position in which the auxiliary ratchet positionsthe primary pawl in the ratchet release position. The secondary pawl ispivotally mounted to the housing via a secondary pawl pin joint and ismovable between an auxiliary ratchet holding position in which thesecondary pawl is positioned to hold the auxiliary ratchet in theprimary pawl enabling position, and an auxiliary ratchet releaseposition in which the secondary pawl is positioned to permit movement ofthe auxiliary ratchet to the disabling position. The secondary pawl maybe biased towards the auxiliary ratchet holding position. The gear ispivotally mounted to the housing via a gear pin joint.

In a further embodiment, the gear has a first gear drive surface that isengageable directly with a secondary pawl drive surface on the secondarypawl. Rotation of the gear to a secondary pawl release position directlydrives the secondary pawl to the auxiliary ratchet release position. Thegear also has a second gear drive surface that is engageable directlywith an auxiliary ratchet drive surface on the auxiliary ratchet.Rotation of the gear to a reset position drives the auxiliary ratchet tothe primary pawl enabling position and causes the secondary pawl to moveto the auxiliary ratchet holding position.

In a still further embodiment, the latch further comprises a resetposition sensor positioned to detect the presence of the gear in thereset position, a secondary pawl locking position sensor positioned todetect the presence of the gear in the secondary pawl locking position,a motor that is operatively connected to the gear, and a controller thatis operatively connected to the motor. The controller receives signalsfrom the reset position sensor that are indicative of whether the gearreaches the reset position, and signals from the secondary pawl lockingposition sensor that are indicative of whether the gear reaches thesecondary pawl locking position. The controller is configured to:

-   -   a) selectively operate the motor to drive the gear towards the        reset position; and    -   b) notify a driver of the vehicle of a problem in the event that        the gear does not reach the reset position after a selected        period of time passes after step a) is initiated,    -   and is configured to:    -   c) selectively cut power to the motor to cause movement of the        gear towards the secondary pawl locking position; and    -   d) carry out at least one action in the event that the gear does        not reach the secondary pawl locking position after a selected        period of time passes after step a) is initiated, wherein the at        least one action is selected from the group of actions        consisting of: notifying a driver of the vehicle of a problem        with the vehicle latch; and drive the gear via the motor towards        the secondary pawl locking position.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects will be more readily appreciated havingreference to the drawings, wherein:

FIG. 1 is a perspective view of a vehicle having a door, which has avehicle latch;

FIG. 2A is a plan view of the latch shown in FIG. 1 with a portion ofthe housing of the latch omitted and in a secondary pawl lockingposition;

FIG. 2B is a plan view of a portion of the latch shown in FIG. 2A in thesecondary pawl locking position;

FIG. 2C is a plan view of a portion of the latch shown in FIG. 2A in thesecondary pawl locking position;

FIG. 3 is a view of the latch shown in FIG. 2A illustrating forcesacting on components of the latch;

FIG. 4 is a plan view of a portion of the latch shown in FIG. 2A leavingthe secondary pawl locking position;

FIG. 5A is a plan view of the latch shown in FIG. 2A in a secondary pawlrelease position;

FIG. 5B is a plan view of a portion of the latch shown in FIG. 5A in thesecondary pawl release position;

FIG. 6A is a plan view of the latch shown in FIG. 2A in a resetposition; and

FIG. 6B is a plan view of a portion of the latch shown in FIG. 6A in thereset position.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a vehicle 10 that includes a vehiclebody 12 and at least one vehicle door 14. The vehicle door 14 includes alatch 20 that is positioned on an edge face 15 and which is releasablyengageable with a striker 28 on the vehicle body 12 to releasably holdthe vehicle door 14 in a closed position. An outside door handle 17 andan inside door handle 16 are provided for opening the latch 20 (i.e. forreleasing the latch 20 from the striker 28) to open the vehicle door 14.An optional lock knob 18 is shown and provides a visual indication ofthe lock state of the latch 20 and may be operable to change the lockstate between an unlocked position and a locked position.

FIGS. 2A and 2B are front views of the latch 20. The latch 20 includes ahousing 22 to which a primary ratchet 24 (which may, for convenience, bereferred to as the ratchet 24) is pivotally mounted via a primaryratchet pin joint 21 for rotation about a primary ratchet pivot axis 26mounted in the housing 22. The ratchet 24 pivots between a fully closedposition wherein the striker 28 (shown schematically in stippled lines)is captured in a slot 29 by a hook 30 of the ratchet 24, as shown inFIG. 2A, and an open position (FIGS. 5A and 5B) wherein the striker 28is not trapped by the hook 30 and is free to move out of the slotpresented by the ratchet 24. In the view shown in FIG. 2A the ratchet 24rotates clockwise to move from the closed position to the open position.

The ratchet 24 is biased towards the open position via a ratchet biasingmember 31. The biasing member 31 may be any suitable type of biasingmember, such as, for example, a torsion spring. A striker bumper 32 ismounted in the housing 22 (underneath the ratchet 24) to cushion againstthe striker force of impact and a ratchet bumper 34 is also mountedabout a post 36 provided in the housing 22 to cushion against theratchet force of impact.

An auxiliary ratchet 44 is also pivotally mounted in the housing 22 viaan auxiliary ratchet pin joint 45 for movement about an auxiliaryratchet pivot axis 46. A primary pawl 47 is pivotally mounted to theauxiliary ratchet 44 via a primary pawl pin joint 49 for movement abouta primary pawl pivot axis 51. The auxiliary ratchet 44 is movablebetween a primary pawl enabling position (FIG. 2A) and a primary pawldisabling position (FIG. 5A). In the primary pawl enabling position theauxiliary ratchet 44 permits the primary pawl 47 to move to a ratchetlocking position to hold the ratchet 24 in the closed position, as shownin FIG. 2A. In the primary pawl disabling position (FIG. 5A) theauxiliary ratchet 44 prevents movement of the primary pawl 47 to theratchet locking position, and instead holds the primary pawl 47 in aratchet release position, as discussed in greater detail below. In theview shown in FIG. 2A the auxiliary ratchet 44 rotates clockwise toreach the primary pawl disabling position.

The auxiliary ratchet 44 includes a cylindrical bore 48 which receives acylindrical stub of the primary pawl 47 for pivotally mounting theprimary pawl 47 into the bore 48, thereby forming pin joint 49 of theauxiliary ratchet 44. This provides a simple means for mounting theprimary pawl 47, which may be formed from a simple stamped or sinteredmetal piece.

The auxiliary ratchet 44 also includes a leg 50 which optionally, asshown in FIG. 2A, terminates in an anvil 52 having a check shoulder 54and a cam lip 56. The auxiliary ratchet 44 may be encapsulated with anelastomeric material and features an optional hollow 58 (FIG. 2A) so asto provide an elastically deformable band 60 for contacting andabsorbing impact against the ratchet 24. A variant shown in FIG. 2B doesnot include the cam lip 56, the band 60 and the hollow 58.

An auxiliary ratchet biasing member 61 located on the opposing side ofthe housing 22 biases the auxiliary ratchet 44 to the primary pawldisabling position. Only the hub portion of the auxiliary ratchetbiasing member 61 is shown in FIG. 2A, (and is shown in stippled lines),for simplicity. The biasing member 61 may include a first tang (notshown) that abuts a capstan of pin 46 and a second tang which cooperateswith a fork (not shown) in the auxiliary ratchet 44 via a slot (notshown) formed in the housing 22.

Referring back to FIG. 2A, the primary pawl 47 includes a check arm 68.In the ratchet locking position the check arm 68 stops the ratchet 24from opening, as shown in FIG. 2A. In the view of FIG. 2A the primarypawl 47 rotates clockwise to move to the ratchet release position.

The angular sweep of the check arm 68 is limited on one side by an edge63 in the auxiliary ratchet 44 and on the other side by the auxiliaryratchet leg 50. A proboscis bumper 72 formed from an encapsulation ofthe primary pawl 47 may be provided to cushion impact of check arm 68against the auxiliary ratchet leg 50. An extension 33 of the strikerbumper 32 may be provided to reduce or cushion impact of check arm 68against the auxiliary ratchet edge 63.

The primary pawl 47 is biased towards the ratchet locking position by aprimary pawl biasing member 74 wrapped around a post 76 provided in theanvil 52 of the auxiliary ratchet 44. One tang (not visible in FIG. 2A)of the biasing member 74 rides against the auxiliary ratchet leg 50, andanother tang 78 abuts the check arm 68 of the primary pawl 47. As thebiasing member 74 is mounted to the auxiliary ratchet 44 rather than thefixed housing 22, the biasing forces on the primary pawl 47 will notvary appreciably as the auxiliary ratchet 44 rotates. In embodimentswherein the post 76 is not provided, the biasing member 74 may beprovided on the housing 22 or at some other location on the auxiliaryratchet 44.

The ratchet 24 features primary and secondary locking surfaces 80 and 82that interact with the check arm 68 of the primary pawl 47. The primarylocking surface 80 provides a fully closed position for the ratchet 24in which the striker 28 is securely ensconced in the slot 31 of theratchet 24 such that the vehicle door 14 is completely closed and thedoor seals 83 are compressed. The secondary locking surface 82 providesa partially closed and locked position of the ratchet 24 wherein thestriker 28 is loosely secured in the slot 31 of the ratchet 24 such thatthe vehicle door 14 is locked but not completely closed against the doorseals 83.

A secondary pawl 84 is pivotally mounted in the housing 22 via asecondary pawl pin joint 85 for movement about a secondary pawl pivotaxis 86 for movement between an auxiliary ratchet holding position wherethe secondary pawl 84 holds the auxiliary ratchet 44 in the primary pawlenabling position, as shown in FIG. 2A, and an auxiliary ratchet releaseposition in which the secondary pawl 84 permits the auxiliary ratchet 44to move to the primary pawl disabling position. In the view shown inFIG. 2A the secondary pawl 84 rotates counterclockwise to reach theauxiliary ratchet release position. The secondary pawl 84 includes ahook shoulder 88 for engaging the auxiliary ratchet check shoulder 54.

The secondary pawl 84 is biased towards the auxiliary ratchet holdingposition by a secondary pawl biasing member 91. The secondary pawlbiasing member 91 may be any suitable type of biasing member, such as,for example, a torsion spring.

It will thus be seen from the foregoing that the latch 20 provides aneccentric double pawl arrangement for lowering release effort. Moreparticularly, as illustrated in FIG. 3, there exists a force Fs on theratchet 24 that is a reaction to the seal force from the door seals 83when the vehicle door is closed. The force Fs along with the ratchetbias force presents a moment M1 on the ratchet 24. The force necessaryto move the primary pawl 47 will thus be related to the coefficient offriction between check arm 68 and ratchet shoulder 38 multiplied by aforce approximately X/Y of Fs, where X is the radial distance betweenthe striker and the ratchet pivot axis 26 and Y is the distance betweenthe primary pawl/ratchet contact area and the ratchet pivot point. Inpractice, the ratio X/Y could be about 40%. Similarly, the force X/Y*Fsapplied to the primary pawl 68 presents a moment M2 about the auxiliaryratchet 44. The force necessary to move the secondary pawl 84 will thusbe related to the coefficient of friction between secondary pawl hookshoulder 88 and auxiliary ratchet check shoulder 54 multiplied by aforce approximately A1/A2 of X/Y*Fs, where A1 is the radial distancebetween the force on the primary pawl 47 and the auxiliary ratchet pivotaxis 46 and A2 is the radial distance between the secondarypawl/auxiliary ratchet contact area and the auxiliary ratchet pivotpoint. In practice, the ratio A1/A2 can be as low as 10-20%. Thus, arelatively low release effort may be required to open the latch 20.

Referring to FIG. 2C, which is a view from the opposite side of thelatch 20 to that which is shown in FIGS. 2A and 2B, the secondary pawl84 includes a first locking surface 92 on a secondary pawl lockingprojection 93. A second locking surface 94 is on a gear lockingprojection 95, which is provided on a gear 96. As shown in FIG. 2C, thegear 96 is rotatably mounted to the housing 22 via a pin joint 97 formovement about a gear axis 99. The gear 96 is driven by a worm 98, whichis itself driven by a motor 100. The gear 96 is movable (i.e. rotatable)between a secondary pawl locking position shown in FIG. 2C in which thesecond locking surface 94 directly blocks (or otherwise cooperates with)the first locking surface 92 to prevent movement of the secondary pawl84 out of the auxiliary ratchet holding position, and a secondary pawlrelease position shown in FIG. 5B, in which the second locking surface94 is out of the way of the first locking surface 92 and thus permitsthe secondary pawl 84 to move to the auxiliary ratchet release position.

Movement of the gear 96 from the secondary pawl locking position (FIG.2C) to the secondary pawl release position (FIG. 5B) may optionallycause the secondary pawl 84 to move to the auxiliary ratchet releaseposition. Specifically, the gear 96 may include a first gear drivesurface 101 on a projection 102 that is engageable with a secondary pawldrive surface 104 on the secondary pawl 84. When the gear 96 is in thesecondary pawl locking position (FIG. 2C), the first gear drive surface101 may be spaced from the secondary pawl drive surface 104. As the gear96 moves from the secondary pawl locking position the gear 96 firstreaches a secondary pawl unlocking position shown in FIG. 4, in whichthe first locking surface 92 moves out of the way of the second lockingsurface 94. After the gear 96 reaches the secondary pawl unlockingposition, further rotation of the gear 96 causes the first gear drivesurface 101 to drive the secondary pawl 84 out of the auxiliary ratchetholding position, until the gear 96 reaches the secondary pawl releaseposition (FIG. 5B), at which point the first gear drive surface 101 hasdriven the secondary pawl 84 to the auxiliary ratchet release position(against the biasing force of the secondary pawl biasing member 91).This permits the auxiliary ratchet 44 to move to the primary pawldisabling position under the biasing force of the auxiliary ratchetbiasing member 61, which in turn brings the primary pawl 47 to theratchet release position, which in turn permits the ratchet 24 to moveto the open position. The seal force Fs from the door seals 83 and thebiasing force from the ratchet biasing member 31 both drive the ratchet24 to the open position, thereby releasing the striker 28 and openingthe vehicle door 14.

The motor 100, which is operatively connected to the gear 96 through theworm 98, may be an electric motor. An electronic controller shownschematically at 106 may be provided and may be operatively connected tothe motor 100, and may selectively send power to the motor 100 toselectively drive the motor 100. The controller 106 may be dedicated tothe latch or may be part of some other controller for the vehicle, suchas a central ECU that is used to control several other functions in thevehicle including, for example, crash detection.

The controller 106 may have any suitable structure, and may, forexample, include a processor, memory and may contain code that permitsthe controller 106 to control the operation of the motor 100 and tocarry out the other functions described herein.

To sense when the gear 96 has reached the secondary pawl releaseposition, a limit switch (such as a “door open” switch, handle switch orboth), by sensing a current spike as a result of a component hitting ahard limit, or by reaching a specified time for applying power to themotor gear assembly 140. An embodiment employs a limit switch inconjunction with a timeout to avoid unnecessary power consumption. Whenthe controller 106 detects that the gear 96 has reached the secondarypawl release position, the controller 106 immediately rotates the gearwheel 96 to a reset position (shown in FIGS. 6A and 6B) to bring thelatch 20 to a reset position to ready the latch 20 to receive andcapture the striker 28 again. To move the gear 96 to the reset position,the motor 100 drives the gear 96, optionally in the opposite directionto the direction used to bring the gear 96 to the secondary pawl releaseposition. Rotation of the gear 96 to the reset position causes movementof the auxiliary ratchet 44 from the primary pawl disabling position tothe primary pawl enabling position via engagement of a second gear drivesurface 109 with an auxiliary drive surface 110 on an arm of a resetlever 112 that rotates about the same axis as the auxiliary ratchet 44(i.e. axis 45). The reset lever 112 is engageable with the auxiliaryratchet 44 by way of a reset lever spring (not shown) that acts betweenthe auxiliary ratchet 44 and the reset lever 112, thereby providing someamount of lost motion available between the auxiliary ratchet 44. Thus,when the gear 96 drives the reset lever 112 (via engagement betweensurface 109 and surface 110), the reset lever 112, in turn, drives theauxiliary ratchet 44 through the reset lever spring. It will be notedthat in FIGS. 2A-6B the housing 22 has been omitted so as to revealcomponents that would otherwise be obscured.

After driving the auxiliary ratchet 44 to the primary pawl enablingposition, further rotation of the gear 96 to the reset position bringsthe gear drive surface 104 away from the secondary pawl 84 therebypermitting the secondary pawl 84 to return to the auxiliary ratchetholding position so as to capture the auxiliary ratchet 44 in theprimary pawl enabling position. Once the gear 96 has reached the resetposition, the controller 106 may stop sending current to the motor 100.As a result, a centering spring shown at 107 in FIG. 2b that may beprovided on a post 108, drives the gear 96 to return to the secondarypawl locking position. In the example shown in FIG. 2b , the centeringspring 107 has a first tang 190 a that engages a first tang receivingwall 191 a on the gear 96 and a second tang 190 b that engages a secondtang receiving wall 191 b on the gear 96. For greater clarity acentering spring is a spring that permits movement of an object ineither of two opposing directions away from a rest position, whereinregardless of which direction the object is moved in, the centeringspring urges the object back towards the rest position.

As can be seen in FIG. 6A, however, even though the auxiliary ratchet 44is in the primary pawl enabling position, the primary pawl 47 is not inthe ratchet locking position; instead the primary pawl 47 abuts a sideedge 114 of the ratchet 24, and not the primary or secondary lockingsurfaces 80 and 82 respectively of the ratchet 24, because the ratchet24 is itself in the open position. The side edge 114 is divided into afirst side edge portion 114 a that extends between the primary andsecondary locking surfaces 80 and 82, and a second side edge portion 114b that continues from the secondary locking surface 80 onwards. When thelatch 20 is in the reset position as described above, the latch 20 isready to receive and capture the striker 28 when the vehicle door 14 isclosed.

Initially, in the reset position, the primary pawl 47 abuts the secondside edge portion 114 b. When the vehicle door 14 is closed and thestriker 28 engages the slot 31 of the ratchet 24, the striker 28 drivesthe ratchet 24 to rotate (counterclockwise in the view shown in FIG. 6A)towards the fully closed position. As the secondary locking surface 82sweeps past the primary pawl 47, the primary pawl biasing member 74falls into contact with the first side edge portion 114 a (from thebiasing force of the biasing member 74). As the ratchet 24 moves intothe fully closed position and the primary locking surface 80 sweeps pastthe primary pawl 47 the primary pawl 47 moves into the ratchet lockingposition to prevent the ratchet 24 from leaving the closed position. Thelatch 20 is then in the closed position shown in FIGS. 2A-2C.

In operation, in the auxiliary ratchet holding position, the secondarypawl 84 can be subject to an inertia force Fi (see FIG. 3) that mayoccur, for example, in the event of a vehicle crash. The force Fi, whichdoes not need to be particularly high given the low release effortsrequired to open the latch 20 as discussed above, will urge thesecondary pawl 84 towards the auxiliary ratchet release position.However, the locking of the secondary pawl 84 by the locking surface 92on the gear 96 advantageously prevents the secondary pawl 84 frompivoting into the auxiliary ratchet release position during a crash.

By locking the secondary pawl 84 in the auxiliary ratchet holdingposition directly with the gear 96, the use of a separate lever andspring is avoided. This simplifies the construction, reduces the costand increases the reliability of the latch 20 relative to a version ofthe latch 20 that would include an additional locking lever and spring.

Referring to FIG. 6B, structure may be provided to verify that the gear96 has reached the reset position. For example, a first Hall-effectsensor shown at 116 may be provided and may be positioned (e.g. on thehousing 22) for sensing the presence of a magnet 118 positioned on thegear 96 when the gear 96 reaches the reset position. The sensor 116 maybe referred to as a reset position sensor and may send signals to thecontroller 106 that are indicative of whether the gear 96 is in thereset position. Thus, when the controller 106 attempts to drive the gear96 to the reset position the reset position sensor 116 can send a signalto the controller 106 to indicate when the gear 96 has reached the resetposition. If, within a selected period of time after sending power tothe motor 100 to drive the gear 96 to the reset position, the controller106 does not receive a signal indicating that the gear 96 has reachedthe reset position the controller 106 may notify the vehicle driver of aproblem with the vehicle latch 20. Notifying the vehicle driver of aproblem with the vehicle latch 20 may, for example entail sendingsignals to an ECU in the vehicle.

In addition to sensing when the gear 96 reaches the reset position, thelatch 20 may be configured to sense when the gear 96 reaches thesecondary pawl locking position. For example, the latch 20 may include asecond Hall-effect sensor 120 that may be referred to as a secondarypawl locking position sensor and that is positioned (e.g. on the housing22) for sensing the presence of the magnet 118 when the gear 96 reachesthe secondary pawl locking position. After cutting power to the motor100 after the gear 96 reaches the reset position, if the controller 106does not receive a signal from the second Hall-effect sensor 120indicating that the gear 96 has reached the secondary pawl lockingposition under the biasing force of the centering spring 107 within aselected period of time (e.g. a second selected period of time), thecontroller 106 may send power to the motor 100 to drive the gear 96 tothe secondary pawl locking position. Upon receiving a signal from thesecond Hall-effect sensor 120 indicating that the gear 96 has reachedthe secondary pawl locking position, the controller 106 may cut power tothe motor 100. If, after a further period of time, the controller 106still does not receive a signal indicating that the gear 96 has reachedthe secondary pawl locking position, the controller 106 may notify thevehicle driver or may send a signal to an ECU in the vehicle indicatingthat there is a problem with the latch 20.

Thus, the controller 106 carries out at least one action in the eventthat the gear 96 does not reach the secondary pawl locking positionafter a selected period of time passes after the cutting of power to themotor 100 is initiated. The at least one action is selected from thegroup of actions consisting of: notifying a driver of the vehicle 10 ofa problem with the latch; and sending power to the motor 100 to drivethe gear 96 towards the secondary pawl locking position.

While the sensors 116 and 120 are shown to be Hall-effect sensors, theymay alternatively be any other suitable kind of sensor. For example, thesensors 116 and 120 could be limit switches and the magnet 118 could bereplaced by a simple protrusion on the gear 96 that closes the contactson one of the limit switches when the gear 96 reaches the reset orsecondary pawl locking positions. Alternatively, the sensor 116 may be asensor to detect a current spike in the current supplied to the motor100 as the gear 96 dead-ends at the reset position. In such anembodiment, structure would be provided to limit one end of the travelof the gear 96 at the reset position, thereby generating the currentspike in the motor 100.

While the embodiments shown in the figures include a ratchet, a primarypawl, an auxiliary ratchet, and a secondary pawl, it is alternativelypossible to provide a different arrangement. In an aspect, the latch mayinclude a ratchet, similar to the ratchet 24, a pawl similar to pawl 84and a gear similar to gear 96. The ratchet is movable between a strikercapture position wherein the ratchet is positioned to retain a strikerand a striker release position wherein the ratchet is positioned torelease the striker. The ratchet may be biased towards the strikerrelease position (e.g. by a biasing member similar to biasing member31). The pawl is movable between a first position and a second position.When the ratchet is in the closed position and the pawl is in the firstposition, the pawl at least indirectly holds the ratchet in the closedposition, and wherein when the pawl is in the second position, the pawlpermits movement of the ratchet to the open position. The pawl may bebiased towards the first position (e.g. by a biasing member similar tobiasing member 91). The gear is movable to a pawl locking positionwherein a gear locking surface on the gear directly blocks movement of apawl locking surface on the pawl so that the gear directly locks thepawl in the second position.

In some embodiments, the pawl is directly engaged with the ratchet. Inother embodiments the pawl may be a secondary pawl, and the vehiclelatch may further include a primary pawl and an auxiliary ratchet,similar to the arrangement shown in the figures.

A feature of some embodiments that can be seen in FIGS. 5a and 6a inparticular, is that the motor 100, the worm 98, the gear 96, the primaryratchet 24, the primary pawl 47, the auxiliary ratchet 44 and thesecondary pawl 84 all extend in planes that are parallel to each other.As a result, the overall shape of the latch 20 may be thinner than somelatches of the prior art. This may be advantageous in permitting thelatch 20 to fit in a vehicle door 14 where space is restricted.

While the above describes one or more particular embodiments, it will beappreciated that modifications and variations may be made to theembodiments described herein without departing from the proper scope ofthe claims appended hereto.

What is claimed is:
 1. A vehicle latch, comprising: a ratchet movable between a striker capture position whereat the ratchet is positioned to retain a striker and a striker release position whereat the ratchet is positioned to release the striker, wherein the ratchet is biased towards the striker release position; a pawl movable between a ratchet holding position whereat the pawl is positioned to hold the ratchet in the striker capture position and a ratchet release position whereat the pawl permits the movement of the ratchet out of the striker capture position, wherein the pawl is biased towards the ratchet holding position; and a gear driven by an electric motor into a pawl locking position in which a gear locking surface on the gear directly blocks movement of a pawl locking surface on the pawl so that the gear directly holds the pawl in the ratchet holding position.
 2. The vehicle latch of claim 1, wherein the gear is operatively connected to the pawl such that rotation of the gear by the electric motor to a reset position causes movement of the pawl toward the ratchet holding position.
 3. The vehicle latch of claim 2, wherein the gear has a first gear drive surface that is engageable directly with a pawl drive surface on the pawl, and wherein rotation of the gear by the electric motor to a pawl release position drives the pawl to the ratchet release position.
 4. The vehicle latch of claim 3, further comprising a gear biasing member that biases the gear towards the pawl locking position from the pawl release position and from the reset position.
 5. The vehicle latch of claim 4, wherein the pawl locking position is between the pawl release position and the reset position.
 6. The vehicle latch of claim 5, further comprising a reset position sensor positioned to detect the presence of the gear in the reset position.
 7. The vehicle latch of claim 6, further comprising a pawl locking position sensor positioned to detect the presence of the gear in the pawl locking position.
 8. The vehicle latch of claim 7, further comprising a controller that receives signals from the reset position sensor that are indicative of whether the gear reaches the reset position, and wherein the controller is operatively connected to the electric motor, wherein the controller is configured to: a) selectively cause the electric motor to drive the gear towards the reset position; and b) notify a driver of the vehicle of a problem in the event that the gear does not reach the reset position after a selected period of time passes after step a) is initiated.
 9. The vehicle latch of claim 7, further comprising a controller that receives signals from the pawl locking position sensor that are indicative of whether the gear reaches the pawl locking position, and wherein the controller is operatively connected to the electric motor, wherein the controller is configured to: a) selectively cause movement of the gear towards the pawl locking position; and b) carry out at least one action in the event that the gear does not reach the pawl locking position after a selected period of time passes after step a) is initiated, wherein the at least one action is selected from the group of actions consisting of: notifying a driver of the vehicle of a problem with the vehicle latch; and causing the electric motor to drive the gear towards the pawl locking position.
 10. A vehicle latch, comprising: a ratchet movable between a striker capture position whereat the ratchet is positioned to retain a striker and a striker release position whereat the ratchet is positioned to release the striker, wherein the ratchet is biased towards the striker release position; a pawl movable between a ratchet holding position wherein the pawl is positioned to hold the ratchet in the striker capture position and a ratchet release position wherein the pawl permits the movement of the ratchet out of the striker capture position, wherein the pawl is biased towards the ratchet holding position; a gear that is operatively connected to the pawl, wherein the gear is rotatable to cause movement of the pawl towards the ratchet holding position, wherein the gear is rotatable to cause movement of the pawl towards the ratchet release position, wherein the gear is rotatable to a pawl locking position to lock the pawl in the ratchet holding position, and wherein the gear is rotatable to a reset position during which the gear causes movement of the pawl to the ratchet holding position; and a reset position sensor positioned to detect the presence of the gear in the reset position.
 11. The vehicle latch of claim 10, wherein rotation of the gear to the reset position causes the gear to move the pawl to the ratchet holding position.
 12. The vehicle latch of claim 11, further comprising a controller that receives signals from the reset position sensor that are indicative of whether the gear reaches the reset position, and wherein the controller is operatively connected to the gear, wherein the controller is configured to: a) selectively drive the gear towards the reset position; and b) notify a driver of the vehicle of a problem in the event that the gear does not reach the reset position after a selected period of time passes after step a) is initiated.
 13. The vehicle latch of claim 12, further comprising a motor, wherein the controller is operatively connected to the motor and the motor is operatively connected to the gear, and wherein the controller is configured to selectively drive the gear towards the reset position via actuation of the motor.
 14. The vehicle latch of claim 10, further comprising a pawl locking position sensor positioned to detect the presence of the gear in the pawl locking position.
 15. The vehicle latch of claim 14, further comprising a controller that receives signals from the pawl locking position sensor that are indicative of whether the gear reaches the pawl locking position, and wherein the controller is operatively connected to the gear, wherein the controller is configured to: a) selectively cause movement of the gear towards the pawl locking position; and b) carry out at least one action in the event that the gear does not reach the pawl locking position after a selected period of time passes after step a) is initiated, wherein the at least one action is selected from the group of actions consisting of: notifying a driver of the vehicle of a problem with the vehicle latch; and driving the gear towards the pawl locking position.
 16. The vehicle latch of claim 15, further comprising a motor, wherein the controller is operatively connected to the motor and the motor that is operatively connected to the gear, and wherein the controller is configured to selectively cause movement of the gear towards the pawl locking position by cutting power to the motor, and to drive the gear towards the primary pawl by sending power to the motor.
 17. A vehicle latch, comprising: a housing; a ratchet mounted to the housing and movable between a striker capture position whereat the ratchet is positioned to retain a striker and a striker release position whereat the ratchet is positioned to release the striker, wherein the ratchet is biased towards the striker release position; a pawl mounted to the housing and movable between a ratchet holding position whereat the pawl is positioned to hold the ratchet in the striker capture position and a ratchet release position whereat the pawl permits the movement of the ratchet out of the striker capture position, wherein the pawl is biased towards the ratchet holding position; and a gear mounted to the housing for rotational movement about a gear axis, wherein the gear is movable to a first position in which the gear blocks movement of the pawl out of the ratchet holding position, wherein the gear is movable to a second position in which the gear holds the primary pawl in the ratchet releasing position, and wherein the gear is movable to a third position in which the gear allows the primary pawl to move toward its ratchet holding position.
 18. The vehicle latch of claim 17, further comprises: a reset position sensor positioned to detect the presence of the gear in the third position; a pawl locking position sensor positioned to detect the presence of the gear in the first position; a motor that is operatively connected to the gear; and a controller that is operatively connected to the motor, wherein the controller receives signals from the reset position sensor that are indicative of whether the gear reaches the third position, and signals from the pawl locking position sensor that are indicative of whether the gear reaches the first position, wherein the controller is configured to: a) selectively operate the motor to drive the gear towards the third position; and b) notify a driver of the vehicle of a problem in the event that the gear does not reach the third position after a selected period of time passes after step a) is initiated, and wherein the controller is configured to: c) selectively cut power to the motor to cause movement of the gear towards the first position; and d) carry out at least one action in the event that the gear does not reach the first position after a selected period of time passes after step a) is initiated, wherein the at least one action is selected from the group of actions consisting of: notifying a driver of the vehicle of a problem with the vehicle latch; and drive the gear via the motor towards the first position. 